Aiming at the seed-dropping problems of clamping cotton-seeds precision dibbler due to vibration in operating, the seeding devices of the dibbler were improved. A seed retaining equipment was designed and installed on the dibbler. Mathematical models that described relationship between the performance indexes and influence factors of the seeding devices were established by applying quadrate regression experiment with general rotary design method. The tendency and regularity of the performance indexes influenced by the factors were analyzed. For the Xinluzao—26 cotton seed, with a goal of maximum single seed index and a given range of multi-seed and missing seed index, length of the clamping boards of the seeding device’s jaw were 4.50mm, width of the jaw were 5.70mm, and opening of the jaw was 7.50mm by parameter optimization. The experiment results showed that the effect of operating vibration was reduced on the improved dibbler.